Tape library cartridge storage and control system

ABSTRACT

A cartridge handling and storage apparatus for use with a multiple axis cartridge handling system includes a mailbox for receiving and disgorging cartridges from a tape library. The mailbox incorporates an aperture in an exposed face of the library, and a door for blocking access to an interior bay of the tape library which is movable by the cartridge handling system for passing cartridges through the mailbox. An ejecting mechanism is provided for cartridges inserted into the mailbox by the cartridge handling system and is actuated by the cartridge handling system. Sensors for a tape library closure door and multi-cartridge magazines held in the library provide the ability for configuration control on cartridges inserted to or removed from the library directly bypassing the mailbox.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to multiple cassette tapestorage libraries with random access cartridge handling. Moreparticularly, the invention provides a tape cartridge handling systememploying an elevator having x, y, and z motion capability with (a) acassette mailbox for insertion and retrieval of individual cassettes and(b) multiple magazines for cassette storage employing a cartridgerelease lever engaged by the elevator mechanism for release ofindividual cartridges from the magazine. The mailbox incorporates aninternal access door actuated by the elevator during retrieval ordeposit of a cassette in the mailbox and a linear cam actuated ejectiondevice engaged and operated by the elevator mechanism.

2. Description of Related Art

Magnetic tape storage libraries employed for off-line storage of datafor archival or short term backup predominantly employ single reel tapecartridges such as the Model 3480 tape cartridge developed by IBMcorporation or the Quantum/Digital DLT cartridge. Operation of the IBM3480 tape cartridge is disclosed in U.S. Pat. No. 4,452,406. The DLTcartridge employs similar functional characteristics in a case havingslightly smaller width and length dimensions than the 3480 cartridge.Each cartridge includes a single reel containing a quantity of magnetictape stored in a substantially rectangular enclosure with an aperture onone major face to receive a rotating capstan for the tape reel. Anaperture in one corner of the cartridge allows access to the free end ofthe tape web by the tape transport unit.

Individual tape transport units are well known in the industry and thedevelopment of tape libraries was accomplished to allow automaticretrieval of cartridges for insertion into one or more tape transportunits. Initial tape libraries employed vertical arrays of tapecartridges which could be sequentially dropped into a loading positionfor introduction into an associated tape transport unit. After use, eachtape cartridge was then ejected from the tape transport unit andreceived in a collection area. However, such approaches lacked randomaccess capability. Storage devices employing magazines capable ofaccepting an array of tape cartridges were developed with verticalmovement of the cartridges relative to a stationary tape transport unitemployed for positioning selected tape cartridges. These devicestypically require significant vertical space to provide magazineactuation travel.

True random access capability has been provided through tape storagelibraries employing magazines having vertically stacked cartridgesaccessible by an elevator retrieval mechanism which transportscartridges to and from the magazine and tape drive unit. Exemplary ofthis type of storage library is the Philips Laser Magnetic StorageDivision (LMS) "Cartridge Stacker Loader" (CSL).

It is desirable to provide multiple magazine capability for increasedcartridge storage while maintaining minimal height and footprint for thetape storage library. While tape storage libraries employing multipleaccess retrieval mechanisms for separate vertical stacks of cartridgesare in commercial development, such devices typically requirenon-standard footprint sizes due to mechanical operating constraints. Itis therefore desirable to provide a multiple magazine tape storagelibrary employing a multiple access retrieval system capable ofsupplying cartridges to multiple tape transport units on a random accessbasis while maintaining a footprint suitable for mounting inconventional equipment rack dimensions.

The use of multiple magazines provides additional complexity ininventorying of cartridges stored in the library. It is desirable thatcassettes be individually removable from the magazines without magazineremoval and that magazines be removable for group handling ofcartridges. To obtain configuration control of cartridges stored in thelibrary, it is therefore desirable that the tape library incorporate aseparate cartridge insertion and removal port or mailbox to allowautomated positioning of cartridges by the tape library system.Additionally, sensing of general access to the magazines and individualmagazine removal or replacement or individual cartridge removal orreplacement from a magazine is desirable for recovering configurationcontrol when the mailbox is not employed.

Cartridge retaining mechanisms on magazines employed within the tapelibrary must allow access to and removal of the cartridge from the frontof the magazine by an operator/user and from the rear of the magazine bythe cartridge manipulation mechanism. Pass-through retaining mechanismssuch as that employed in the Philips LMS CSL tape storage library havedemonstrated satisfactory performance. However, it is desirable toprovide the capability for release of the retention mechanism which isself-aligning and can tolerate dimensional variation imposed byoperation of the cartridge retrieval mechanism.

SUMMARY OF THE INVENTION

A tape storage library incorporating the present invention employsmultiple cartridge magazines, each providing vertically distributedslots for cartridge storage. The magazines are arranged in adjacent,horizontal relation providing an x-y array of cartridges in the tapestorage library. The magazines are removably restrained in a framemounted in a front bay of the tape storage library.

A cartridge retrieval mechanism positioned in an open bay rearwardlyadjacent the magazine frames includes an x-axis frame supporting anelevator platform which incorporates a gripper mechanism for retrievalof individual cartridges. The elevator platform translates along thex-axis frame defining a first motion axis.

The x-axis frame is cantilevered from a pillow block assembly whichtranslates along a y-axis rail defining the second axis of motion forthe cartridge retrieval assembly. Rotation of the cantilevered x-axisframe about the y-axis rail is restrained by a slotted guide or rollingelement mounted proximate one end of the x-axis frame which receives avertical flange mounted parallel to the y-axis rail.

A gripper for cartridge handling is mounted to the elevator. The gripperis aligned with individual cartridges contained within the magazines bythe x and y motion of the elevator and similarly positioned forplacement of cartridges in a tape transport unit. A plurality of tapetransport units is mounted in a bay rearwardly adjacent the baycontaining the x-axis frame. The gripper mechanism provides pass throughhandling of tape cartridges for insertion and removal from the tapetransport units.

A cartridge handling and storage apparatus for a tape libraryincorporating the present invention includes a mailbox for receiving anddisgorging cartridges from the tape library. The mailbox includes anaperture in an exposed face of the library and a door for blockingaccess to an interior bay of the tape library which is movable forpassing cartridges through the mailbox. An ejecting mechanism isprovided for cartridges inserted into the mailbox by the cartridgehandling system.

In the library, a plurality of removable cartridge storage magazines arearranged in an x-y array with each having a plurality of verticallyspaced cartridge storage slots. A closure bar for preventing removal ofcartridges from the front of the magazine is provided which is movablefor manually extracting cartridges. Each magazine also includes amechanism for releasing cartridges from the magazine for extraction froma rear of the magazine.

A closure door is provided for the library which is movable from aclosed position to an open position with the door covering the fronts ofsaid magazines in the closed position. The manipulating system movescartridges between the mailbox, magazine storage slots and at least onetape drive internal to the tape library and is translatable in x, y andz axes.

For interface with the cartridge handling and storage apparatus, themanipulation system includes a means for moving the blocking door, ameans for engaging the releasing means on each magazine, and a means foractuating the ejecting mechanism on the mailbox. In addition, a sensorfor presence of the closure bar for each of the plurality of magazinesin a closed position is actuated by opening of the closure bar orremoval of the magazine. A door position detector is activated bymovement of the door from the closed position to the open position andcartridge configuration is assessed by the system responsive toactuation of the closure bar sensor and the door position detector.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is best understood with reference to the followingdrawings and detailed description wherein

FIG. 1 is a front pictorial view of a tape library incorporating thepresent invention with the front door and left side panel removed;

FIG. 2 is a front pictorial view of the tape library of FIG. 1 with twomagazines and their associated frames removed to display the cartridgeretrieval mechanism;

FIG. 3 is a right side pictorial view of the tape library with the sidepanel removed;

FIG. 4 is a left rear perspective of the tape library with the top andleft side panels removed to display elements of the mailbox andcartridge retrieval mechanism;

FIG. 5 is a pictorial view of the cartridge retrieval mechanism;

FIG. 6 is a front perspective view of the elevator and gripper assembly;

FIG. 7a is a left rear perspective view of the mailbox assembly;

FIG. 7b is a right rear perspective view of the mailbox assembly;

FIG. 7c is a partial perspective view showing the cartridge ejectionassembly;

FIG. 8a is a rear perspective view of a cartridge magazine andassociated frame;

FIG. 8b is a detailed perspective view of a cartridge release actuatoremployed with the magazine and frame of the present invention;

FIG. 9 is a partial perspective view of two magazines and associatedframes employed in the tape library with associated sensing switchassemblies; and

FIG. 10 is a flow chart demonstrating cartridge configuration control bythe tape library system.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, FIGS. 1-4 disclose a multi-cartridge tapelibrary incorporating the present invention. The library is housed in anenclosure 10 which, in the embodiment disclosed in the drawings, issuitable for mounting in a conventional 19 inch electronic equipmentrack. As best seen in FIG. 1, the present embodiment employs threecartridge magazines 12 which are mounted in frames 14 in a front bay orportion of the enclosure designated 16. A cartridge manipulation unit 18is mounted in a second bay of the enclosure generally designated 20immediately rearward of the magazine bay. The cartridge manipulationunit includes an x-y position system which incorporates an x-axis frame22 and a y-axis rail 24. The x-axis frame is cantilevered from a pillowblock assembly 26 carried by the y-axis rail. An elevator assembly 28 issupported by the x-axis frame. Translation of the elevator assemblyalong the x-axis frame defines a first motion axis for the cartridgemanipulation system. Translation of the pillow block assembly on they-axis rail defines a second axis of motion for the cartridgemanipulation system.

The elevator assembly incorporates a gripper mechanism 30 for retrievalof individual tape cartridges. The gripper mechanism is movably mountedto an elevator platform 32 and provides a belt drive train 34 whichcooperates with opposing roller assembly 36. Details of the elevatorassembly are best seen in FIGS. 6a-6h. The gripper assembly translateson a third motion axis providing +z and -z motion for the cartridgemanipulation assembly. Relative position of the elevator assembly in thelibrary is best seen in FIG. 2 which provides a front isometric view ofthe enclosure with two magazines and their associated mounting frameremoved. A tape cartridge 46 shown carried within the gripper assembly.

A third bay in the enclosure generally designated 38 houses four tapedrive units 40 for the embodiment shown in the drawings. Each tape driveis integrally mounted in a support chassis received in frame 42 withinthe enclosure. The cartridge insertion aperture 44 of each tape driveunit is exposed to the cartridge manipulation system operating in theimmediately adjacent bay.

An electronics board 48 is mounted in the aft bay of the libraryenclosure adjacent the tape drive stack in the embodiment shown in thedrawings. A central processing unit, memory and electronic controlcircuitry for the library are mounted on the controller board. Operatorinterface is accomplished through a control panel 50 mounted on thefront face of the enclosure which includes a display 52 forcommunication with the operator and input keys 54 for manual input bythe operator. Communications by the tape library with a user network orother computer devices is accomplished through industry-standardcommunications interfaces.

A tape cartridge mailbox assembly 56, seen in FIG. 3 and shown in detailin FIGS. 7a-7c, is included in the tape library to allow automatedhandling of cartridges for individual insertion and removal from thelibrary. The mailbox assembly incorporates a cartridge receivingaperture 58 on the library front face. Cartridges inserted to themailbox are retrieved by the cartridge manipulation assembly for directplacement in a tape drive assembly or cataloguing in an open magazineslot. Similarly, tape cartridges retrieved by the manipulation assemblyfrom the tape drive or a magazine location are unloaded from the librarythrough the mailbox to be retrieved by an operator.

The tape library as disclosed in the drawings also allows manualcartridge manipulation by an operator through door 60, which exposes thethree magazines when opened. The individual magazines are removable fromthe library, allowing handling of cartridges in seven-unit multiples,and individual cartridges are removable from the magazines directly byrotation of the cartridge stop 62, best seen in and described in detailwith regard to FIG. 9, into an open position, allowing access toindividual cartridges stored in the magazine.

As best seen in FIG. 5, the elevator assembly is carried by the x-axisframe 22, which incorporates two parallel guide rails 64. One rail istraversed by a linear bearing 66 which is mounted to the top of theelevator platform. The second rail is engaged by gliders which areadjustably mounted to bracket 72, which is in turn mounted to theelevator platform. The contact the second rail tangentially at the topof the rail thereby providing tolerance relief for spacing of the guiderails. The entire elevator assembly traverses along the x-axis framewhile the x-axis frame is in turn translated along the y-axis rail forpositioning of the gripper assembly in an x-y plane for cartridgemanipulation alignment.

The gripper shown in FIG. 6 is movable bidirectionally relative to theelevator platform in a +z and -z direction, as will be described ingreater detail subsequently. A traction assembly having a friction drivebelt and cooperating reaction rollers, mounted in spaced relation toreceive a cartridge between the belt and rollers, provides thecapability to frictionally engage cartridges in the library array anddraw them through the gripper. The gripper belt drive train 34incorporates peripheral rollers 74 which are mounted on pivotingbrackets 76. These brackets are in turn mounted to the gripper frame 78by pivot pins. Inner rollers 82 are mounted coaxially with the pivotpins.

A drive capstan 84 is centrally mounted in the belt drive train,supported by a side cradle. The capstan includes a central drive gear,which engages the gripper belt, and upper and lower bearing mountscarried in the side cradle above and below the drive gear. The capstanshaft extends below the side cradle to engage a pulley belt driven byreversible stepper motor 94, which is mounted to a bottom plate 96 ofthe gripper frame. Two roll pins are mounted in the side cradle oneither side of the capstan, urging the gripper belt onto the drive gearand maintaining belt tension.

An inboard arm on each of the pivot brackets carries a linear camfollower. During translation of the gripper assembly in the +/-z-axisdirections, the cam followers are controlled by the contour of the racein linear cam block. The outboard cam follower, with respect to therelative +/-z-axis motion of the gripper assembly, is driven into alaterally translated portion of the linear cam for the extended portionof the gripper travel. Location of the cam follower opposite the pivotpoint from the peripheral roller urges the peripheral roller inward forincreased pressure on a tape cartridge engaged by the gripper mechanism.Conversely, the inboard cam follower, relative to the direction ofmotion of the gripper mechanism, remains in the untranslated portion ofthe cam track. Adjustment of the center of pressure exerted by thegripper belt on a cartridge being manipulated is adjustable at thelateral extents of the +/-z-axis gripper motion by contouring of thelinear cam track.

The reaction roller assembly 36 cooperates with the belt drive train. Aswith the belt drive train, cooperating reaction rollers 106 are mountedon pivoting brackets 108. The rollers are carried on an outboard arm ofthe bracket with respect to a pivot pin while the inboard arm of each ofthe pivoting brackets carries a cam follower. As previously describedfor the belt drive train, during translation of the gripper assembly inthe +/-z-axis directions, a linear cam block controls the cam followerssuch that the outboard cam follower with respect to the relative+/-z-axis motion is driven into laterally translated portions of the camtrack. Based on the location of the cam follower opposite the pivotpoint from the outboard rollers, the pivoting bracket urges the rollersinward, increasing pressure on the tape cartridge in cooperation withthe outer roller of the belt drive assembly.

A detailed description of the structure and operation of the elevatorand gripper assembly is provided in co-pending patent application Ser.No. 08/716,682, the disclosure of which is incorporated herein in itsentirety by reference.

In an exemplary operating sequence, the gripper assembly is positionedadjacent a cartridge slot in one of the tape library magazines or themailbox by the x-y positioning system. The gripper assembly is extendedin the +z direction with the drive belt operating in a first direction,as will be described in greater detail subsequently. As the grippermechanism approaches the extent of its +z motion, the cam followers onthe drive belt roller brackets and reaction roller assembly bracketscause the belt and reaction rollers to "pinch" the cartridge which,urged by the drive belt rotated in a forward direction by the steppermotor, is withdrawn from its storage slot into the gripper assembly. Thegripper assembly is then withdrawn to a zero position on the z-axisproviding even force distribution between both sides of the belt trainand roller assembly. The gripper mechanism is then positioned adjacentthe cartridge aperture of one of the plurality of tape drives and thebelt drive is engaged to pass the tape cartridge through the grippermechanism. As the cartridge enters the tape drive, the gripper assemblytranslates in the -z direction for affirmative positioning of thecartridge in the tape drive. As the gripper assembly approaches theextent of its -z travel, the cam followers on the pivoting brackets urgethe belt drive roller and outboard rollers into higher pressure contactwith the tape cartridge providing affirmative motion control forinsertion of the cartridge into the tape drive.

Upon ejection of the tape cartridge from the tape drive, the describedmanipulation process is reversed, with the belt driven by the steppermotor in a reverse direction, to return the cartridge to its magazineslot or other handling as appropriate. It should be noted that thecartridge manipulation system is available for handling of othercartridges with other tape drives during operation of the first drive.

FIG. 5 displays the features of an x/y positioning system incorporatingthe present invention. The cantilevered mounting of x-axis frame 22 toy-axis pillow block 26 allows mounting of the x-axis stepper motor 200substantially within the x-dimension of the frame. X-axis positioning ofthe elevator assembly is accomplished by the x-axis stepper motordriving lead screw 202 through a drive belt extending between pulleys204. A lead nut engaging the lead screw is constrained in mounting block206 which is fixed to the elevator platform 32. Reversible rotation ofthe lead screw by the x-axis stepper motor positions the elevatorassembly at any desired location along the rails 64 in the x-axis frame.

Y-axis pillow block 26 incorporates a bearing receiving y-axis rail 24and a lead nut engaging y-axis lead screw 208. A unitary support bracket210 mounted to the floor of the tape library structure, as best seen inFIG. 4, supports the bottom of the y-axis rail and a bottom bearing 212for the y-axis lead screw. A y-axis stepper motor 214 is mounted to anaft portion of the bracket and drives the y-axis lead screw through belt216. A top bracket 218 mounted to the top of the library enclosurereceives the top of the y-axis rail and houses a top bearing 220 for they-axis lead screw.

Rotation of the x-axis frame about the y-axis rail is prevented byslotted glider 222 which is received on vertical flange 224 extendingbetween the floor and top of the library enclosure as best seen inFIG. 1. The slotted glider or, alternatively, a rolling element, isattached to the back plate 226 of the x-axis frame proximate a first endplate 228 of the x-axis frame. The slotted glider provides fordimensional tolerance relief between the y axis rail and the verticalantirotation flange. The back plate 226 is mounted to pillow block 26. Asecond end plate 230 completes the x-axis frame with parallel guiderails 64 and x-axis lead screw 202 supported and constrainedintermediate the end plates. In the embodiment shown in the drawings,the x-axis stepper motor 200 is mounted intermediate the second endplate of the x-axis frame and the y-axis pillow block. Mounting of themotor inboard of the end plates, with the belt drive train nestedagainst and parallel to one end plate, significantly reduces the x-axisfootprint for the x/y positioning system reducing the overall width ofthe footprint for the tape library. Similarly, centrally cantileveredmounting of the x-axis frame to the y-axis rail through the pillow blockallows mounting of the y-axis components in the third bay of the libraryenclosure adjacent the tape drive mounting frame, as best seen in FIG.4. The dimensions required for the second bay in which the cartridgemanipulation system operates is thereby reduced in both the x and zdirections.

The x/y positioning system disclosed, in addition to providing anabbreviated x/z footprint for the manipulation system, provides asubstantially unlimited y-axis expansion capability. The y axis rail isextendable to the vertical extent of the y dimension of the cartridgestorage array. Stacking of multiple tiers of three magazine frames, suchas those disclosed in FIG. 1, allows library expansion while maintaininga reduced width footprint for mounting in conventional electronic racks.

The mailbox assembly previously described with respect to FIG. 3 isshown in detail in FIG. 7. In the embodiment shown in the drawings, themailbox assembly is mounted in the tape library enclosure above thecartridge magazine frame. The mailbox assembly comprises a cartridgereceiving box 300 having a front frame 302 mounted substantially flushwith the front face of the tape library enclosure exposing the cartridgeinsertion and removal aperture 58, best seen in FIG. 1. As shown inFIGS. 7a and 7b, the front frame of the mailbox incorporates a mountingtab 304 to secure the mailbox to the front face of the tape library.Left side 306 and right side 308 extending rearward from the front framesupport mailbox top 310 and are attached to mailbox floor 312. Acartridge inserted into the mailbox is received on shelves 314 spacedabove the mailbox floor as best seen in FIG. 7b. A sloping engagementapron on the cartridge spacer shelves accommodates slight misalignmentof the gripper assembly during passing of a tape cartridge from thegripper assembly to the mailbox. A pivoted door 316, best seen in FIG.7a is attached to the mailbox sides by arms 318. The pivoting doorprecludes inadvertent access to the interior of the tape librarypreventing an operator from reaching through an open mailbox, or pushinga tape cartridge entirely through the mailbox. A contact lever 320 isattached to the door for engagement by the cartridge elevator assembly.The mailbox door is opened by positioning the elevator below the mailboxand raising the elevator to contact the lever causing the door to pivotto an open position as the elevator aligns the gripper assembly with themailbox for extraction or replacement of a tape cartridge.

The mailbox incorporates a detent spring 322, which engages anindentation in the tape cartridge for positioning. An operator insertinga cartridge into the mailbox presses the cartridge to the detent, whichabuts the end of the cartridge with the mailbox door providingsufficient exposure of the cartridge sides to allow contact by thegripper assembly extended in the +z direction. A cartridge positioned inthe mailbox by the manipulation assembly for removal by the operator ispositioned to the inner detent by the gripper assembly. A cam actuatedcartridge ejection assembly 326 is then engaged by the gripper to urgethe cassette to the outer detent position where it can be grasped by anoperator and removed from the mailbox.

The cartridge ejection assembly is best seen in FIGS. 7b and 7c. Aplunger 328 is reciprocally engaged by a barrel 330, which incorporatesa spring urging the plunger into the extended position. A cartridgecontact lever 340 extends from the plunger through a linear cam track342 cut in the barrel wall. With the plunger in the extended position,the cam track rotates or retracts the lever downwardly to a positionbelow the cartridge spacer shelves 314. Upon pressure from the gripperassembly in the +z direction urging the plunger into the barrel, thelever is moved from the downward position cam track portion 344 to anupward position cam track portion 346, which raises the lever intoalignment for contact with the rear face of the cartridge. Continuedmotion by the gripper assembly in the +z direction urging the plungerfurther into the barrel causes the lever to force the cartridge outwardin the mailbox to the outer detent position. Return of the gripperassembly to a zero position on the z-axis allows the plunger to returnto its original position causing the lever to rotate downward in the camtrack allowing a tape cartridge to be passed through the mailbox.

Operator handling of tape cartridges may bypass the cartridge mailboxassembly as previously described. Cartridges may be manipulated by theoperator in groups of seven by removal and insertion of cartridgemagazines and individually from magazines, mounted in or removed fromthe library, by rotating the cartridge restraining bar on the magazine.As previously described, the magazine employed in the present inventionhas been employed on prior Philips LMS CSL systems. Details of themagazine and magazine frame employed in the present invention are shownin FIG. 8a. Tape cartridges 46 are received in slots 402 in themagazine. The magazine allows cartridges to be withdrawn from the frontside of the magazine by the operator or the rear side of the magazine bythe cartridge manipulation system in the tape library. Each magazineslot is provided with a cartridge securing system, which precludesinadvertent removal of cartridges from the magazine. The operator mayremove a cartridge from the front face of the magazine by rotating thecartridge retaining bar 62. The retaining bar provides a physicalbarrier to removal of the cartridges in its closed position. In the openposition, any of the seven cartridges in the magazine may be removed.

A lever actuated retaining mechanism in each slot of the magazineprecludes removal of individual cartridges from the back side of themagazine. Release of the lever actuated retaining mechanism isaccomplished by insertion of a release pin through aperture 404associated with each slot. In prior art embodiments a pin carried by thecartridge manipulation mechanism was employed to actuate the release.However, tolerance problems in alignment of such an actuation pin withthe appropriate aperture precluded consistent satisfactory results. Thepresent invention employs a plurality of release actuators 406 mountedto the magazine frame and individually associated with a slot of themagazine. Details of the actuator are shown in FIG. 8b.

The actuator incorporates a lever portion 408 on which release pin 410is mounted. A pivot pin 412 is integrally formed in the actuator and isreceived by a J-clip 414, best seen in FIG. 8a, with the respectiverelease actuator removed from the magazine frame. The J-clip extendsthrough slot 416 in a tail portion of the actuator allowing rotationalmotion of the lever about the pin. Restoring force for the lever isprovided through paired spring legs 418 extending peripherally from thelever. Depressing the lever, as will be described subsequently, impartstorsional forces to the attaching portions of the spring legs creating arestoring force upon release of the lever. An alignment tab 420extending from the magazine frame, as best seen in FIG. 8a is receivedin slot 422 intermediate the release lever and one of the restoringspring legs. Motion of the release lever is constrained in the openposition by stops 424 extending from the tail of the actuator forcontact with the magazine frame and stop 426 in the closed position,which again contacts the side of the frame. A release lever is closed ordepressed by contact from an actuation paddle 428 mounted on thepivoting frame of the gripper assembly, as best seen in FIG. 6a, withangled contact 430 extending from the end of the lever.

In retrieving a cartridge from the magazine, the gripper assembly isaligned with a cartridge slot by the elevator. Actuation of the gripperin the +z direction results in urging the pivoting brackets of thegripper assembly inward for contact with the cartridge therebysimultaneously urging the paddle inward contacting the lever and urgingrelease pin 410 into the release aperture 404, freeing the cassette forremoval from the magazine. Upon translation of the gripper in a -zdirection, the paddle and hence release lever are relaxed outwardlythereby returning the lever to the unactuated position under restoringforce from the spring legs 418. Vertical tolerance in the actuation ofthe release system is accommodated by the width of the actuation paddleon the gripper assembly. While slight horizontal misalignment isaccommodated by the angle of the lever contact and the correspondingangle of the actuating paddle.

Configuration control for cartridges contained in the tape library isaccomplished automatically by the system for cartridges inserted andremoved through the mailbox. To reduce overhead in recoveringconfiguration of the cartridge compliment in the library when magazinesor cartridges are individually manipulated by an operator, the presentinvention incorporates door and magazine actuation sensors. A librarydoor sensor 600 senses the open or closed position of library door 60. Amagazine sensor 602 accomplishes a dual purpose sensing removal of theentire magazine and sensing actuation of the cartridge restraining barwithout removal of the magazine from the tape library.

As best seen in FIG. 9, the magazine sensor comprises two elements forthe embodiment disclosed in the drawings. A rotating cam 603a is engagedby the magazine closure bar and urged downward into contact with amicroswitch 603b. Spring loading of the cam urges the cam upward intocontact with the closure bar. When the closure bar is rotated to allowremoval of a cartridge, the cam rotates upwardly, disengaging themicroswitch which provides a signal to the tape library controller,indicating actuation of the magazine closure bar.

Similarly, the door closure switch comprises a strike plate and clasp601a, which when engaged by the door, depresses microswitch 601b.Opening the tape library door pulls the striker plate outward untilreleased by the door clasp, activating the microswitch which in turnprovides a signal to the tape library controller indicating a door opencondition.

The central processing unit for the tape library logs a door opencondition sensed by position switch 600. Similarly, actuation of acartridge restraining bar or removal of a magazine is detected by one ofthe magazine switches and sensed by the CPU. Recovery of libraryconfiguration is accomplished by cataloging of cassettes in any magazinewhich has been removed or the restraining bar has been actuated. Thisapproach reduces the overhead in reacquiring configuration control bylimiting the cataloging to magazines that have been physicallymanipulated by an operator. For magazines which have not been somanipulated, prior configuration of the cartridges has not beendisturbed.

Cataloging of cartridges in the library is accomplished through the useof a bar code scanner 604, best seen in FIG. 4. Cartridges retrievedfrom the library mailbox or a magazine slot are positioned by themanipulation system in front of the sensor during configurationconfirmation or initial insertion through the mailbox.

In the embodiment of the invention shown in the drawings, an active casescanner 604, best seen in FIG. 4, is mounted at the proper scan angleemploying an insulating support box containing a scan window. Insulationof the active case, from the structure of the library, is required forelectrical performance of the scanner and the enclosure, with scanningwindow, provides a dust free environment assuring performance of thescanner. Positioning of the scanner in the natural manipulation path ofcartridges retrieved from or returned to the mailbox simplifiesmechanical operation of the library.

As previously described, the tape library system maintains configurationcontrol of the cartridges contained within magazines in the library. Ifthe operator chooses to remove and/or insert cartridges directly intomagazines in the library as opposed to inserting cartridges through themailbox, the identity of the inserted or removed cartridges must bedetermined to maintain configuration control in the library. The presentinvention precludes the requirement for physically inventorying allcartridges present in the system by employing separate sensors for eachmagazine in the tape library and an initiating door position detector.

As shown in FIG. 10, if the operator opens the tape library door, theposition detector is actuated which initiates the configuration routineand each magazine sensor is polled as identified in blocks 701-703. Uponclosure of the tape library door, block 700, since each of the magazinesis individually sensed to determine removal of the magazine as a wholeor cycling of the cartridge retainer bar for removal of individualcartridges from the magazine, the configuration recovery system firstsamples the first magazine sensor to determine if the magazine has beenremoved or the retainer bar cycled, block 710. If the sensor indicates asignal, a routine is initiated for retrieving each cartridge in themagazine in sequence. A start address pointer is set in block 711 andthe cartridge corresponding to the counter is retrieved from themagazine as shown in block 720. The cartridge manipulation systempositions the cartridge in front of the bar code reader, which scans thebar code, block 721, and the cartridge is returned to the slot fromwhich it was retrieved. The configuration system determines if the barcode scans corresponds to a cartridge currently identified in theconfiguration list in block 722 and if the cartridge is not onepreviously identified, a configuration list is updated in block 723. Thecounter is then incremented, block 724, and tested to determine if allslots in the magazine have been retrieved in block 725. For the presentembodiment in which seven cartridges are present in each magazine, uponincrementing of the counter to a value of eight greater than the startaddress, the system returns to sense the second magazine as shown inblock 712. If magazine two has a flag set, the counter is set, block713, and the retrieval routine is initiated. If magazine two has notbeen removed or the retainer bar cycled, sensing of magazine three isaccomplished in block 714. If magazine three has a flag set, the counteris set, block 715, and the retrieval routine is initiated.

Only magazines which have been physically manipulated by the operatorare scanned thereby reducing time and complexity in recoveringconfiguration control for the library.

Having now described the invention, as required by the patent statutes,those skilled in the art will recognize modifications and substitutionsfor the elements of the embodiments disclosed. Such modifications andsubstitutions are within the scope and intent of the invention asdefined in the following claims.

What is claimed is:
 1. A mailbox for receiving and disgorging cartridgesfrom a tape library having a cartridge manipulation system with threeaxis translation capability for cartridge handling, said mailboxcomprising:an aperture in an exposed face of the library; means forblocking access to an interior bay of the tape library, said blockingmeans moveable by contact with the cartridge manipulation system forpassing cartridges through the mailbox; and means for ejectingcartridges inserted into the mailbox, said ejecting means operativethrough engagement with the cartridge manipulation system.
 2. A mailboxas defined in claim 1 wherein the mailbox includes a rectangular frame,and wherein the blocking means comprises a rear door pivotally mountedto at least one side of the rectangular frame and having a projectingcontact lever adapted for engagement by a surface on the cartridgemanipulation system whereby translation of the manipulation systemsubsequent to contact of the lever rotates the door to expose a rearaperture in the frame permitting translation of a cartridge to or fromthe mailbox.
 3. A mailbox as defined in claim 1 wherein the mailboxincludes a rectangular frame and the ejecting means comprises:a barrelincorporating a linear cam track mounted proximate one corner of theframe; a plunger received within the barrel for reciprocating movementfrom an extended position to a depressed position; a lever extendingfrom the plunger through the linear cam track, the linear cam trackurging the lever into a first retracted position with the plunger in anextended condition allowing clear translation of a cartridge through themailbox frame and urging the lever into a raised position during motionof the plunger from said extended position to said depressed positionfor contact of a rear face of a cartridge present in the mailbox frame,said lever urging the cartridge outwardly from the mailbox frame uponcontinued motion of the plunger toward the depressed position; and meansfor operative engagement of the plunger by the cartridge manipulationsystem whereby translation of the manipulation system urges the plungerfrom the extended position to the depressed position.
 4. A mailbox asdefined in claim 3 further comprising at least one spacer platformmounted to a bottom of the mailbox frame for supporting a cartridgetherein and wherein the ejecting means is mounted to the mailbox frameproximate a bottom corner of the frame and the linear cam race isprofiled to provide retraction of the lever below a top surface of thespacer with the plunger in the extended position.
 5. A cartridgeejection apparatus for a framed tape library mailbox, the apparatuscomprising:a plunger reciprocally engaged by a barrel having a linearcam track extending therethrough; a lever connected to the plunger andextending through the linear cam track, said lever retracted by theliner cam track for clearance of a cartridge with the plunger in anextended position and the lever extended for contact with a rear surfaceof the cartridge during travel by the plunger from the extended positionto a depressed position; a cartridge manipulation apparatus including agripper mechanism moveable for translation in an axis parallel to theplunger; and means for engagement of the gripper and plunger wherebytranslation of the gripper in said axis urges the plunger from theextended position to the depressed position subsequent to disgorgementof a cartridge from the gripper to the mailbox frame.
 6. A cartridgerelease apparatus for tape library magazines having vertically spacedcartridge storage slots employing a release aperture for cartridgesstored therein, the apparatus comprising:a frame surrounding a cartridgemagazine having a release aperture; a release actuator incorporating alever portion; a pivot pin integrally formed in the actuatorintermediate the lever portion and a tail portion of the actuator; aJ-clip extending from the frame and engaging the pivot pin; at least oneresilient leg extending from the actuator proximate the pivot pin saidresilient leg imparting a torsional restoring force to said actuatorupon movement of the lever portion to a depressed position; a first stopextending from the tail portion of the actuator to contact the framewith the lever portion in an undepressed position; a release pin mountedto the lever portion for operative engagement with the release apertureof the magazine with the lever portion in the depressed position; andmeans for engaging the lever portion mounted to a gripper assembly forcartridge extraction from and insertion to the magazine wherein thegripper assembly translates along an axis substantially parallel withthe lever portion and includes means for contacting the engagement meansto urge the lever portion to the depressed position.
 7. An apparatus asdefined in claim 6 wherein the tail portion includes a slot abutting thepivot pin and receiving the J-clip therethrough for engagement of thepivot pin.
 8. An apparatus as defined in claim 7 wherein the resilientrestoring leg comprises:a lever portion extending substantially parallelto the actuator lever and terminating in a standoff foot; and aresilient portion extending substantially perpendicular to the leverportion and actuator lever portion proximate the pivot pin and furthercomprising an alignment tab extending from the frame intermediate theactuator lever portion and lever portion.
 9. An apparatus as defined inclaim 6 wherein the engagement means comprises an angled contactextending from an end of the actuator lever portion opposite theactuator tail portion, said contact extending at an angle inward towardsaid frame and a contact paddle mounted on the gripper and having acomplementary angle to accommodate misalignment.
 10. An apparatus asdefined in claim 9 wherein the contact paddle has a vertical dimensionpredetermined to accommodate alignment tolerance between the gripper andactuator lever portion during operation of the cartridge manipulationsystem.
 11. An apparatus as defined in claim 6 further comprising asecond stop extending from the actuator lever portion intermediate thepivot pin and release pin for contact on the frame with the leverportion in the depressed position.
 12. An apparatus for cartridgeconfiguration control in a tape library comprising:a plurality ofremovable cartridge storage magazines arranged in an x-y array and eachhaving a plurality of vertically spaced cartridge storage slots; andmeans for preventing removal of cartridges from a front of the magazinesaid preventing means moveable for manually extracting cartridges; meansfor sensing presence of the preventing means for each of said pluralityof magazines in a closed position said sensing means actuated by openingof the preventing means or removal of said each magazine; and means forinventorying cartridges present in a magazine responsive to actuation ofsaid sensing means corresponding to the magazine.
 13. An apparatus asdefined in claim 12 wherein the preventing means comprises a closure barrotatably mounted to each magazine and extending substantially thevertical extent of the magazine, said bar rotatable from a closedposition abutting an exposed end of cartridges present in the magazineto an open position exposing the cartridges for removal from themagazine and said sensing means comprises:a cam actuated by rotation ofthe closure bar to the open position and further actuated by removal ofthe magazine from the tape library; and a microswitch responsive toactuation of the cam.
 14. An apparatus as defined in claim 13 furthercomprising:a closure door for the library, moveable from a closedposition to an open position, said door covering the fronts of saidmagazines in said closed position; and means for detecting doorposition, said detecting means actuated by movement of the door from theclosed position to the open position and wherein the means forinventorying cartridges is further responsive to actuation of saiddetecting means.
 15. A cartridge handling and storage apparatus for atape library, said apparatus comprising:a mailbox for receiving anddisgorging cartridges from a tape library, said mailbox havinganaperture in an exposed face of the library, means for blocking access toan interior bay of the tape library, said blocking means movable forpassing cartridges through the mailbox, and means for ejectingcartridges inserted into the mailbox; a plurality of removable cartridgestorage magazines arranged in an x-y array and each havinga plurality ofvertically spaced cartridge storage slots, means for preventing removalof cartridges from a front of the magazine, said preventing meansmovable for manually extracting cartridges, and means for releasingcartridges from the magazine for extraction from a rear of the magazine;a closure door for the library, movable from a closed position to anopen position, said door covering the fronts of said magazines in saidclosed position; means for manipulating cartridges between the mailbox,magazine storage slots and at least one tape drive internal to the tapelibrary, said manipulating means translatable in x, y and z axes andhavinga means for moving said blocking means, a means for engaging saidreleasing means, and a means for actuating said ejecting means; meansfor sensing presence of the preventing means for each of said pluralityof magazines in a closed position said sensing means actuated by openingof the preventing means or removal of said each magazine; means fordetecting door position, said detecting means activated by movement ofthe door from the closed position to the open position; and means fordetermining cartridge configuration responsive to actuation of saidsensing means and said detecting means.